The major aim of this project is to characterize immunoglobulin responses in helminth infections (primarily filariasis and schistosomiasis) with emphasis on IgE production, regulation and modulation. Sensitive radioimmunoassays have been developed and utilized for quantitating IgG and IgE antibodies. Qualitative characterization in terms of what antigens are being recognized in various clinical forms of the disease is being carried out to understand immune recognition and its implication in the pathogenesis and/or defense of the disease. These studies would in addition provide information about antigens with better specificity in immunodiagnosis or epidemiologic studies. Finally, in vitro production and regulation of IgE synthesis is also under investigation to better understand the control mechanisms of IgE production.